1. Field of the Invention
The present invention relates to a weapon interface system evaluation apparatus and method for evaluating the operational status of a weapon interface system and, more specifically, to a weapon interface system evaluation apparatus and method for evaluating the operational status of a weapon interface system having both a self-contained remote terminal and a bus controller, such as a system complying with MIL-STD-1553.
2. Description of the Related Art
Broad interchangeability of weapon systems, e.g., missiles, is a major design goal for many modern military aircraft. For example, an aircraft that is capable of supporting both air-to-air and air-to-surface weapon systems may perform both air engagement and ground support roles. Each weapon system, however, has its own requirements for use. Various and generally unique inputs are required by each weapon type for status monitoring, targeting, arming, and ejecting the weapon system.
Military aircraft are typically designed to carry a plurality of weapon systems, some of which may be of the same design and some of which may be of a different variety. A central computer within the aircraft, referred to here as an aircraft controller, is responsive to pilot or aircrew commands and communicates with each weapon system to monitor status, perform launch preparation, and execute launch commands. These weapon systems are coupled to a tailored electronics or avionics system which responds to the aircraft controller. This avionics system serves as an interface between the aircraft controller and the weapon systems, and is referred to here as a weapon interface system ("WIS"). The WIS receives commands from the aircraft controller and translates these commands to provide data usable by one or more weapon systems. The WIS also receives power from the aircraft and distributes this power to the weapon systems. In addition, the WIS controls and provides launch power to the weapon system ejectors which eject the weapon systems from the aircraft.
A WIS, together with its wiring and ejectors, is referred to here as an unloaded weapon carriage assembly. An unloaded weapon carriage assembly joined with its weapon systems and mounted on a wing-attachable pylon or weapon bay-installable launcher, is referred to here as a loaded weapon carriage assembly. Each weapon system, e.g., an individual missile of a given type, and its corresponding ejector are referred to here as a weapon station.
The WIS typically comprises a separate electronic box, or set of cables and boxes, mounted on a pylon or launcher and physically detachable from the aircraft to facilitate interchangeability and maintainability. Accordingly, the WIS is separately storable and testable.
As noted, the aircraft may simultaneously carry a number of weapon systems of differing designs, each weapon system design having its own input requirements and providing its own outputs. In addition, the aircraft controller must be able to communicate with a selected weapon system, regardless of its design, independently of other weapon systems, so that, for example, the weapon system can provide status to the aircraft controller and the aircraft controller can specifically designate that weapon system for launch. This latter feature is important, for example, to appropriately launch the specific type of weapon system designated by the pilot or aircrew, and to systematically select the various weapon systems of a given design so that symmetric weight distribution and aerodynamic stability of the carrier aircraft can be maintained.
In the past, it has been necessary to extend cables from the aircraft controller to each WIS and from the WIS to each weapon system to provide a direct and independent communication link. This design is unattractive because it unnecessarily adds to the weight of the aircraft, generates unnecessary power and cooling requirements, and causes unnecessary electromagnetic inteference.
In response, MIL-STD-1553, entitled Military Standard--Aircraft Internal Time Division Command/Response Multiplex Data Bus, was introduced, which with its revisions and updates is incorporated herein by reference. MIL-STD-1553 replaced the multiple cable design with a dual-redundant data bus design having only two shielded twisted pair cables--a primary bus and a backup bus. The dual-redundant data bus provides a common bus for connecting the aircraft controller to each of the weapon carriage assemblies (each at its respective WIS). The aircraft controller provides a multiplexed signal over one of the dual-redundant data buses at a time to each WIS on the various weapon carriage assemblies. The WIS of each weapon carriage assembly has a remote terminal for receiving signals from and transmitting signals to the aircraft controller over the MIL-STD-1553 bus; a central processing unit ("CPU") for processing these signals, selectively interacting with the various weapon carriage assembly components, and responding to the aircraft controller; and a MIL-STD 1553 bus controller for controlling transmissions between the CPU and the weapon systems over MIL-STD 1553 weapon system buses. Firmware in the WIS, i.e., non-volatile machine language code used by the CPU, allows the WIS to determine which signals on the aircraft MIL-STD-1553 bus are directed to a given weapon system under control of that WIS.
The WIS/weapon system interface requirements for a weapon system capable of using a MIL-STD-1553 WIS are set forth in MIL-STD-1760, entitled Military Standard--Aircraft/Store Electric Interconnection System, which with its revisions and updates is incorporated herein by reference. MIL-STD-1760 weapon systems include a MIL-STD-1553 remote terminal which is designed and operates identical to the remote terminal of the WIS.
Immediately prior to deployment of a loaded weapon carriage assembly, the WIS is separately tested to verify its operational status. Upon successful completion of this test, the MIL-STD-1760 weapon systems are mated to the WIS to comprise a loaded weapon carriage assembly, as described above. The loaded weapon carriage assembly is then mated with the carrier aircraft.
Test equipment is used to perform the separate test of the WIS prior to mating it with the weapon systems. The test equipment is designed to test the operational status of the WIS to verify that all critical components are in working order and all connections are sound.
In the past, various designs have been employed for the WIS test equipment. These designs typically include active devices which simulate the operational status monitoring and command signals provided by the aircraft controller during mission performance. These test instruments, for example, provide simulated signals to the WIS and monitor its response to verify the integrity of the various internal components of the WIS. Since conventional WIS test equipment often includes active devices such as microprocessor controller chips for performing the range of test functions required to verify the operational status of the WIS, they are usually relatively complex.
The weapon system and its WIS are often stored, tested and mated with the aircraft in forward areas, i.e., in areas that may be near fronts of military conflict. These forward areas are typically remote areas where fixed buildings and reliable power sources are unavailable. However, the complex design of conventional test equipment has been such that reliable power sources and controlled environments are required for proper operation. Where these controlled conditions are unavailable, support measures such as transportable shelters are required for proper operation of the test equipment. These test equipment support measures typically require special logistics and support measures themselves, and can place an undesired burden on already taxed transportation, operational and maintenance resources during a military conflict.
Accordingly, an object of the present invention is to provide a WIS evaluation apparatus and method for quickly and reliably evaluating the operational status of a WIS.
Another object of the present invention is to provide a WIS evaluation apparatus and method for evaluating the operational status of a WIS where the WIS is in compliance with MIL-STD-1553 both for receiving data from the carrier aircraft and for communicating with MIL-STD 1760 weapon systems.
A further object of the invention is to provide a WIS evaluation apparatus and method which is operable over a wide range of environmental conditions without the need for environmental protection such as buildings or hangers.
A still further object of the invention is to provide a WIS evaluation apparatus and method which can be operated using standard power sources typically available in a field environment, such as standard aircraft power carts.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.